Pyrazolo diazepine-8-carboxylates

In an extension of previous work on conjugated enamine carbonyl derivatives, reaction of the pyrazolone 91 with IV.lV-disubstituted hydrazines on heating in an alcohol solvent afforded the hexahydropyrazolo[4,3-Michael-type addition of the alcohol to a pre-formed pyrazolo-diazepine, was excluded <06T8126>. 

Hydrazines react with 6-chloro-l-hexynylphosphonates 74 to provide the corresponding azaheterocyclic phosphonates 75 in good yields and purity <07TL3213>, while pyrazolo[4,3-c]diazepine carboxylates 77 were prepared by heating the to-enamine 76 with 1,2-dimethylhydrazine in methanol or ethanol at reflux <07H(71)657>. 

While pyrazolo[3,4-d][l,2]diazepines have been obtained by cycloaddition of 2-diazopropane to 1,2-diazepines (72TL2851, 74T2851, 80TL4507, 85CB4682, 91T2925, 91JHC369), isomeric p5rrazolo[4,3-d][l,2]diazepines are mentioned in the literature only once. Namely, in the heterocycliza-tion of 5-acetylenylpyrazole-4-carboxylic acid hydrazides under the... 

Cl5H13NO, 6,7-Dihydro-6-methyl-5H-dibenz[c,e]azepin-5-one, 39B, 211 Cl 5H1 i,Ni,02 f 4,5-Benzo-8,11,11 - trimethyl-1, 2,7,1 0-tetraazatricyclo-[7.3,0.0 ]dodeca-2,9-diene-6,12-dione, 46B, 273 Cl5H1sBr2N, 1,1-Bis(bromoethyl)-l,2,3,4-tetrahydroacridine, 46B, 273 Cl5H15N2O5, Methyl 8-methoxycarbonylmethyl-2-oxo-2,3,3a,8-tetrahyd-ro-1H-pyrazolo[5,1-a]isoindol-3-carboxylate, 41B, 346 Cl5H16N2O2, 5,7-Dihydroxy-6,6-dimethyl 6,7-dihydrodibenzo[d,f](1,3)-diazepine, 44B, 256... 

C28H16N2, (3-Pyrida-3-(2,6))(6-benza-6-(1,4 2,5))(9-pyrida-9-(2,6))-spiro[5.5]undecaphane-l,4,7,l0-tetraene, 43B, 384 C24H21N3O3, 3aa,40,8/3-3a,4-Dihydro-3-oxo-2,3a-diphenyl-4,8-etheno-3H-pyrazolo[1,5-c](1,3)diazepine-7(8H)-carboxylic acid ethyl ester, 46B, 300... 

---